1. Field of the Invention
The invention relates to a light, narrow, lightweight cast vault wall panel construction which will withstand burglarious attack and which may be used for either door slabs or modular panels to fabricate vaults to protect valuables.
Also, the invention relates to modular panels that may be assembled to form a vault during construction of a building or in existing buildings. Such panels also may be used to expand a vault size at any time. Such vault wall panels may be removed and reassembled at another site.
In addition, the new reinforced concrete modular panels enable vault walls to be provided thinner than traditional reinforced concrete vault walls while offering acceptable burglarious protection.
Further, the invention relates to a superplasticized steel fiber reinforced concrete product and manufacture, intended for use in safes, vault doors, vault walls, etc. which reinforced concrete product is superior to conventional reinforced Portland cement concrete for such applications.
Finally, the invention relates to a reinforced concrete composition containing extraordinarily high amounts or dosage rates of superplasticizing, water-reducing admixtures along with extraordinarily high steel fiber contents to produce a concrete product having outstanding strength and impact resistance as compared to conventional Portland cement concrete ordinarily composed of Portland cement, fine aggregate, coarse aggregate and water.
2. Description of the Prior Art
The amount of water used in conventional concrete has a major effect on the resulting engineering properties of the concrete. As the water content increases, most of the engineering properties of the concrete are adversely affected. Additionally, even when the water content falls within an acceptable range, the flexure strength of the concrete and, hence, its resistance to cracking is relatively low. Such difficulties are avoided by the substantially reduced water content of the composition of the invention while providing the desired fluidity for casting from conventional mixers.
Conventional prior art vault construction usually has involved thick walled vaults formed by conventional Portland cement concrete cast in place. The improved panel construction of the invention eliminates cast-in-place problems and the improved modular fiber reinforced concrete panel construction permits reduced wall thickness while satisfying burglary resistant requirements.
Prior art proposals for cast metal fiber reinforced concrete vault walls have used metal fiber reinforcement concepts of the prior art in seeking to improve cast vault wall protective characteristics. Examples of such prior art include U.S. Pat. Nos. 4,377,977, 3,429,094, 4,388,874 and 4,389,948.
Essentially, the composition of the reinforced concrete in such prior art proposals involves simple mixtures of steel fibers, hydraulic cement, sand, and water. Specifically, the cement component in U.S. Pat. No. 4,377,977 composition is expansive cement, asserted in combination with the steel fibers to create a "self-stressing" material.
However, the difficulties remain that are encountered with the typical strength levels of conventional Portland cement concrete having a water content sufficient to enable mixing in a conventional manner in conventional mixers and to provide fluidity for pouring in molds.
Thus a need has existed in the field of protective vault construction for a castable concrete wall and door panel construction with improved engineering properties providing required burglarious attack resistance in thinner walls than those required for equivalent attack resistance formed of conventional cast reinforced concrete, which panels may be used to construct removable, expandable, dismantlable and reassemblable vault structures in new or existing buildings.